The present invention relates to a fuel tank for an automobile which comprises a tank main body for storing fuel, a filler pipe for supplying the fuel to the tank main body, and a first breather pipe for connecting the upper space of the tank main body to the neighboring portion of a fuel supply opening formed in the upper end portion of the filler pipe, wherein, when an upper surface level of the fuel within the tank main body (hereinafter, referring a fuel liquid surface) is present at a given height, at least part of the filler pipe is closed by the fuel.
A filler pipe, which is used to supply fuel to the tank main body of a fuel tank for an automobile, preferably, may extend upwardly from the upper space of the tank main body in order to be able to realize smooth fuel supply. In fact, however, there exists a case in which, depending on the position of the body frame of the automobile, the filler pipe cannot be disposed in the above-mentioned preferred position. For example, there is a case that the lower end of the filler pipe is connected to the lower space of the tank main body (see JP-A-2001-30773, JP-A-2001-80372).
FIG. 6 shows the above-mentioned conventional fuel tank T. In this tank T, in the upper end of a filler pipe 02 which extends obliquely upwardly from the lower space of a tank main body 01, there is formed a fuel supply opening 03.
The upper space of the tank main body 01 is connected to the neighboring portion of the fuel supply opening 03 of the filler pipe 02 by a breather pipe 04. Since the lower end of the filler pipe 02 is connected to the lower space of the tank main body 01, when the fuel liquid surface of the tank main body 01 is present at a given height, the lower portion of the filler pipe 02 is closed by the fuel. Such closed state can occur not only in a case where the filler pipe 02 has such a bent shape as to extend horizontally from the upper space of the tank main body 01 and then extend upwardly, but also in a case where the fuel is caused to stay in the bent portion of the filler pipe 02 due to the inclination of the road on which an automobile is stopping.
In the closed (partially filled) state of the filler pipe 02, in case where an fuel supply nozzle 05 is inserted into the fuel supply opening 03 and fuel is supplied into the fuel supply opening 03 from the fuel supply nozzle 05, an air layer is confined in the middle portion of the filler pipe 02, that is, the air layer, which is confined there and there is nowhere it could go, flows backward. Because of this, the fuel, which is stored in the portion of the filler pipe 02 that exists upwardly of the air layer, can flow back to the fuel supply opening 03. In case where the fuel flows back to the fuel supply opening 03 in this manner, the fuel is applied over the nozzle of the fuel supply nozzle 05 to thereby operate the automatic stop mechanism of the fuel supply nozzle 05, which makes it impossible to supply the fuel any further.